Knowing When Not to Use Priceline

Even if you're a frequent Priceliner, you're fighting against the odds if you try to use Priceline for some kinds of trips. If you're just looking for a weekend away, prices are generally low on your route, or you think you may have to change your plans, Priceline will probably be more hassle than it's worth.

For weekend trips

Never buy Priceline airline tickets for a weekend trip. If you try to buy tickets for Saturday and Sunday, you could get a flight leaving at 10 p.m. on Saturday and returning at 6 a.m. on Sunday. That's not much of a weekend!

To save money with Priceline on a three- or four-day weekend, buy an air-and-hotel package. Priceline's Playtime Guarantee ensures you'll spend at least 44 hours at your destination for a two-night trip and 64 hours for a three-night trip (unless you're going to Las Vegas, where, apparently, there are no guarantees).

That means if you book for Friday and Sunday, the worst-case scenario is flights that let you spend from 2 p.m. Friday to 10 a.m. Sunday at your destination, or 8 p.m. Friday to 4 p.m. Sunday. That's not so bad.

For last-minute trips, Priceline's Weekender packages even let you choose roughly what time of day you want to fly.

When airfares are low

Airlines offer incredible sales nowadays through their own Web sites. If airlines are duking it out on your route, undercutting each other with great low fares and setting new records for cheap seats, Priceline won't be able to touch the fares they're offering. And if a low-fare airline like Southwest or JetBlue keeps prices low on your route, Priceline probably won't be able to beat them.

On the other hand, if last-minute fares look sky-high or the cheap seats are all sold out, it's time for Priceline.

Airlines deliver some incredible deals during low seasons (times of the year when fewer people are flying) for various destinations. Priceline isn't about to beat most super-low winter fares to Europe, or summer fares to the Bahamas. Even if no competitive airfare sale is going on, airlines typically cool it with the Priceline seats when their regular prices are at rock bottom.

When your trip can't be booked on one airline or with two stops

In order for Priceline to book a ticket, you must be able to fly your whole route on a single, Priceline partner airline. You can change planes, but you must stay on the same airline or one of its codeshare partners. And you must get there with no more than two stops each way.

This rule is more complicated than it seems because of codeshares (when one airline pretends to be another airline that it's friends with, selling seats on the second airline using the first airline's flight numbers). US Airways and United, for example, pretend to be each other all the time. Priceline counts codeshares as one airline.

When you may have to cancel or change your trip

Priceline tickets are nonrefundable and nonchangeable. That's not quite as bad as it sounds, but you should treat it as if it is. In other words, don't bid on Priceline if you think you may have to cancel or change your flight for any reason at all.

Priceline's travel insurance provides some protection against illness, car accidents on the way to the airport, or terrorist attacks at your destination. And, of course, if your airline cancels your flight and can't put you on another one, Priceline will give you your money back.

Using Priceline to connect with a cruise is a bad idea. If your cruise is cancelled, you'll be left in the lurch unless you bought good third-party travel insurance, like Travel Guard's Cruise Guard product. Priceline's airline-ticket travel insurance doesn't cover missed cruise connections.

Even if you don't have travel insurance, Priceline may make a one-time exception and refund your money. Asking is always worthwhile.

If you want to book anything other than a standard round-trip flight

Priceline only books standard round-trip tickets. On Priceline, you can't buy a one-way ticket (a ticket taking you only from Point A to Point B), or a three-legged ticket (a ticket taking you from Point A to Point B to Point C, and then directly back to Point A), or an open-jaw ticket (a ticket taking you from Point A to Point B, and then from Point C back to Point A).

If one-way fares are very high on your route through the airlines, you can buy a round-trip ticket with Priceline and only use the first half. This strategy is called throwaway ticketing, because you're essentially using half of the ticket and throwing away the other half.

You can only throw away the second half of a ticket. If you miss the first half, your airline will automatically cancel the rest of your ticket.

Airlines hate throwaway ticketing. Even though it's legal for you to do, it lets you avoid insane airline fare policies. So airlines claim they'll dock your frequent-flier account if they catch you doing it. Realistically, they don't bother people who only rarely throw away tickets. To be on the safe side, don't give the airline your frequent-flier number if you plan to throw away your return ticket.

If you're someone Priceline won't accept

Sorry, kids: You must be 18 to fly solo with Priceline. That's because some airlines don't allow unaccompanied minors on the last flight of the day, and Priceline very well may put you on the last flight of the day. Under-18s can fly through Priceline if they're accompanied by someone older.

Priceline also rejects Canadians. It demands you have a credit card with a billing address in the United States, the United Kingdom, or one of the Pacific Rim countries where it does business.

For places Priceline usually doesn't fly

All Priceline flights must start in the United States (including Puerto Rico and the U.S. Virgin Islands). You can't use Priceline for flights to the United States from any other country, even Canada.

Don't bother with Priceline for tickets to India, Africa, or any but the largest South American and Asian cities. Eastern Europe is another weak area for Priceline.

Within the United States, if Northwest, Southwest, or Alaska Airlines dominates the city you're flying to, you're unlikely to find a great deal on Priceline. Those three airlines don't sell tickets through Priceline. So flights to Memphis, Minneapolis, and Nome will probably be pretty hard to find.